Fluorine Aided Stabilization of Pt Single Atoms on TiO2 Nanosheets and Strongly Enhanced Photocatalytic H2 Evolution

Trapping sites in single atom (SA) catalysts are critical to the stabilization and reactivity of isolated atoms. Herein, we show that anchoring of Pt SAs on TiO2 nanosheets is strongly aided by lattice incorporated fluorine species. Tailoring the speciation of fluorine on TiO2 nanosheets is a key factor for uniform and stable dispersion of the Pt SAs and high efficiency in Pt SA co-catalyzed photocatalytic H2 production. Fluorine-stabilized uniformly dispersed Pt SAs on the (001) surface of TiO2 can provide a remarkable photocatalytic activity (a H2 production rate of 45.3 mmol h–1 mg–1 Pt for 65 mW/cm2 365 nm light). This high (maximized) efficiency can be achieved with a remarkably low loading amount of Pt SAs on TiO2 nanosheets (0.03 wt %), which is far superior to Pt nanoparticles on a TiO2 nanosheet with the same or a higher loading amount. F-stabilized Pt SAs on TiO2 nanosheets also exhibit an excellent stability in long-term photocatalytic reactions.